Gents:

Could someone clear me up here: when sighting in a rifle should one measure the distance from the muzzle to the ground and then place the bulls eye the same height at X distance?

Further, if one wanted their rifle to be say, 2 inches high at 100 yards, where would that place the bullet at 50 yards?

Thanks!

Generally the difference in height of gun and target will not make much difference unless you are shooting at extended ranges and steep angles. If your bench is 3ft. off the ground and your target is 5 feet, no difference. Just make sure the berm is high enough.Your second question can't be answered as it depends on several things including height of scope above barrel, bullet weight and velocity etc. Generally I bore sight my gun (looking through the breech and adjusting the scope) at 25 and if it is in the black at 25 then it will be on paper (8 1/2x 11) at 100. Then I adjust from there. Just FWIW.
Peter.

Bullseye height is not that important, unless you are talking a 30 degree angle. Most target stands are chest high, while the bench is waist high, and you'll never know a difference.
2 in. high at 100 yds will vary at 50 depending on the round. 30-30, with a rainbow like trajectory, will be diff than say a 22-250 that shoots more like a lazer, but one inch high at 50 should be fairly close for general purposes, assuming you don't have access to a 100 yd. range.

Use this to figure it out.

JBM Ballistics

A few simple inputs and it will tell you everything you need to know.

Yep a ballistic calculator is the way to go. Granted not perfect but damn close enough for hunting.
Let's see here My 7X57 is less then one inch high at 50 yards to give me two inches at 100. But my 45 ACP would have to be about three feet high to give me 2 inches at 100.

22-250 220 swift set at 2 inches high at 50 to equal 2 inches high at 100 = LASER Not really but close

We're in the middle of our gun club's public deer rifle sight-in month. We see dozens of new rifles or new scopes at the 25 yard line every weekend. Rifles with the current crop of wider scopes and taller mounts are best zero'd an inch low at 25 or dead on at 50 and then checked at 100 and 200. And there is no substitute for actually checking at the range you intend to shoot. We have a 300 yard line too but few to none of the box or two a year men who report taking quarter mile shots (yeah, the guys with the Remington 74xx series rifle wearing no-name scopes in see-through mounts) have ever shot at the 200 yard line let alone at 300.

quote:

Originally posted by jsl3170:
Gents:

Could someone clear me up here: when sighting in a rifle should one measure the distance from the muzzle to the ground and then place the bulls eye the same height at X distance?

Further, if one wanted their rifle to be say, 2 inches high at 100 yards, where would that place the bullet at 50 yards?

Thanks!

As mentioned the heigth of the target doesn't make any difference that you will notice unless the angle to the target is great. If you are shooting off a normal type shooting bench rest and it is relatively level to the target the target can be at ground level or chest high or somewhere in between.

As to bullet impact at 50 yards; It depends on what the desired range zero is, the heigth of the scope above the bore, the BC of the bullet and the actual velocity.

Larry Gibson

Thanks everyone! In this case, here is the additional info: CZ 550 LH in 375 H&H. Will be loading 300 grain NPs over 71 grains of IMR 4350 for approx muzzle velocity of 2282 fps. Scope in question is a Zeiss 2.5-8x32 sitting in Talley QD mounts.

I am not at all sure, but it seems somewhere in my brain that I have read that a bullet strike at 27 yards on a target will strike the same place on the target at 100 yards.
When I am sighting in a rifle for the first time, I place a target at 27 yards and bore sight with that. Then I shoot one shot and then shoot at the bullet hole. That gives me the exact adjustment I need to make and then I move to 100 yards.
I've never checked to see if it was exact but it's awfully close.

quote:

Originally posted by jsl3170:
Thanks everyone! In this case, here is the additional info: CZ 550 LH in 375 H&H. Will be loading 300 grain NPs over 71 grains of IMR 4350 for approx muzzle velocity of 2282 fps. Scope in question is a Zeiss 2.5-8x32 sitting in Talley QD mounts.

Assuming a 1.7" scope height and hitting 2" high at 100 yards;

25 yards; 0
50 yards; +1"
100 yards; +2"
150 yards; + 1"
170 yards; 0
200 yards; -2.2"
250 yards; -8"
300 yards; -16.5"

Larry Gibson

quote:

Originally posted by stillbeeman:
I am not at all sure, but it seems somewhere in my brain that I have read that a bullet strike at 27 yards on a target will strike the same place on the target at 100 yards. ...

Are you suggesting it makes no difference what the Velocity nor Balliatic Coefficient happen to be?

In the short distance of 25 yard impact vs. 100 yard impact, scope mounting hight is the largest variable. A low mounted scope vs. a realy high mounted scope on the same rifle will have two very different impact points at 100, if both are zero at 25 yrds....it's just math.

Uhhh, this is why I was so circumspect in my statment. however, when I am sighting in a rifle, I bore sight it at 25yards, and then shoot it at 25 yards and adjust it until the bullets are striking the same hole. Then I move to 100 yards. As I said, I've never checked to see if it was exact but its close enough to where final adjustments are a snap.
It seems the info came from an old J Oconnor article about him shooting the heads off of sage grouse using that info.
The idea is sound if not exact since the bullet has got to pass thru the line of sight at some point before it begins it's descent to the target.

HC, I'm not sure. I haven't "picked" at it that much. As I posted, it just seems to work. I don't see why it wouldn't be constant. Just the arc would be flatter. But then, that would mean the bullet would break the line of sight further along. Beats me. I'm sure the nit pickers will take it apart but I'll be like the bumble bee. Just flying merrily on my way.

Today at my range I was shooting my 30/06 with 180 grn Sierra Game Kings. I messed with this a bit and re-sited for zero @100 then shot a couple rounds at 25 yards the two shots hit 1.3/16 low same hole group. 100 yards in this test is the first intersection of bullet/hold the second is farther away but I didnt shoot past 100 today.

The 25 yard bore sight meathod is what I use on all my bolt guns....and yes by doing this it makes 100 a snap.

.

I can give you a 1 shot site in procedure that works for me.
Put a target at 25 yds.
Shoot 1 shot.
Put the gun on a steady rest so it can't move.
Put the crosshairs on the target you just aimed at.
Move the cross hairs to the bullet hole. (without moving the gun)
You are now done...put your target at 100 or 200 yds and check zero. You will probably be slightly high at 100yds and very close to dead on at 200.

I found the same Idea works fantastic for adjusting once you are shooting at long range. The other day I went to shooting some 130ttsx's (300 win) at 200 yds. I got a tight group about 5" high and 1" right. I put the gun into the lead sled...aimed at my target...move crosshairs to center of group....next shot went right into the orange dot at 200 yds.